Hydro-pneumatic or hydraulic jack devices



March 1, 1966 M. cousm 3,237,931

HYDRO-PNEUMATIC OR HYDRAULIC JACK DEVICES Filed Oct. 10, 1965 FZgJ a 3Fig.2 4

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:"6 /z' if; -12-- 529 28 WYEW United States Patent 3,237,931HYDRU-PNEUMATIC 0R HYDRAULIC JACK DEVICES Maurice Cousin, 62 RuePergolese, Paris, France Filed Oct. 10, 1963, Ser. No. 315,154 Claims.(Cl. 26764) Hydropneumatic or hydraulic jack devices are presently used,as is well known, in various industrial applications, and particularlyfor the suspension and shockabsorption or damping of vehicles. Inaddition to the fact that liquid leakages from such jacks are notgenerally recovered, nor recoverable, the deflection of such jacks undera permanent load varies definitely as a function of such load. Theeffective damping of such presently known jacks, generally accomplishedby other resilient means, is hardly adapted to the variations of thispermanentload.

The present invention has for its object the provision of improved jacksof this type, enabling the recovery and the restoration of any leakageof useful liquid to the inside of the jack, the correction to a constantlevel of their deflection characteristics and of their damping when thepermanent overload varies, all or part of these functions beingautomatically secured by using only the liquid inside the jack under theeffect of the movements thereof, and more particularly under the effectof the movements caused by the wheels on passing over the inequalitiesand obstacles of the road, without resorting to auxiliary loading andreloading means (pumps), nor to any external control (trimmingcorrection) of the fluid level within the jack, or to a stabilitycorrection (anti-rolling bar members).

The invention is wholly described in the following specificationreferring to the appended drawings, wherein:

FIGURES 1, 2 and 3 are cross-sectional views through the axis of threealternative embodiments, respectively, of jacks according to theinvention, FIGURE 3 being a fragmentary view.

FIGURE 4 is a cross-sectional view, perpendicular to said axis, alongthe line a-a' of FIGURE 2.

A hydraulic jack according to the invention, as illustrated in FIGURE 1,indicated by the general reference number 1, comprises a cup-shapedmember 2 including a gas chamber 3 and a diaphragm 4, secured inposition on a cup-shaped member 6 of the jack body by means of lockingring 5, said diaphragm separating the gas contained in chamber 3 fromthe connecting fluid 7 in a chamber 16. The device is generallyconnected by means of two lugs such as 8 and 9, at the two opposite endsthereof, between the mobile parts of the system, and specificallybetween the wheel and the frame of the vehicle to which it is adapted.However, said jack may also be of the hydraulic type, as shown inFIGURES 2 and 3, and in this case it will be connected as at 10 to anyauxiliary resilient system.

As is known in prior art jacks, harmful fluid leakages usually occuroutside the chamber 16, particularly at the joint between piston 12 andthe body 11 thereof, or between the piston-rod 13 and the guidingsupport or bearing guide 14 thereof, and flow towards chambers 17 and15, wherefrom they are, in exceptional cases, recovered by an auxiliaryarrangement, but are more often lost.

In the arrangements according to the present invention, these leakagesare automatically recovered in the chamber 15 closed on purpose, andreincorporated in chamber 17 (below piston 12), then in the alreadymentioned upper chamber 16 above said piston, this being effected by thesole reciprocating motion of the various elements of the jack, in such amanner that, initially, while piston 12 is overloaded, the preliminaryfilling of Patented Mar. 1, 1956 chamber 17 below piston 12 should becompuisory, and that, on the other hand, the subsequent discharge fromchamber 17 towards chamber 16 takes place during the opposite strokeduring which piston 12 is discharging and that, finally, any overflowmay be automatically discharged from chamber 16 to chamber 17.

Thus, referring more particularly to FIGURES 1 through 4, it will benoted that chamber 15, below the guiding support 14, may be placedeither directly under the resiliently deformable bellows-shaped cap 18,as shown in FIGURE 2, secured at both its ends to said support 14 and,at the lower portion of the figure, to

the bell-shaped member 19, or, as illustrated in FIG- URE 1, below thebell-shaped portion 19, extended by an expansion chamber 211, and belowa diaphragm 21 and cap 18 (top of FIGURE 1).

Piston 12 carries a control valve member 22, adapted to cause the fluiddischarge to pass from chamber 17 t0 chamber 15, but not in the oppositedirection. Bearing guide 14 carries a similar first control valve member23 opposing, totally or partially, the liquid flow from chamber 17 tochamber 15, but may open a free passage to the liquid in the oppositedirection, and a second similar control valve member 24 (FIGURES l and3), opposing partially the flow of liquid from chamber 15 towards space26, but leaving a free passage in the opposite direction, from space 21towards chamber 15.

The control members 22, 23 and 24 may be of any desired type and member22 may be located anywhere else than in the support 14, for instance,above support 14 (FIGURE 1) and inside the bell-shaped member 19;members 23 and 24 are however complementary to one another, one thereofbeing closed, while the other is open, and vice versa.

In FIGURES 1 and 3, the upstroke of piston 12 increases the volume ofchamber 17, while shrinking that of chamber 15, the incompressibleliquid of which tends to leak into the spaces 17 and 21), but closesmember 24, thus resulting, through a viscous braking on space 21 towardschamber 15, in the compulsory filling of chamber 17 through thecorrelatively open member 23; in FIGURE 2, the filling of chamber 17 isurged by the tension of cap 18.

The subsequent downstroke of piston 12, in the case of FIGURE 1, in thebody 11, increases the volume of chamber 15, while decreasing that ofchamber 17, the liquid of which, being incompressible, closes member 23and opens member 22, i.e. opens therethrough the liquid re-incorporationof chamber 17 in space 16, whereas the valve member 24 (FIGURE 3),opened subsequently to the closing of member 23, causes the liquid fromspace 20 to enter chamber 15, under stress due to diaphragm 21; inFIGURE 2, this liquid will remain constant under the stress of cap 18.

The overflow from chamber 16 is conducted below piston 12 in body 11, bya particular liquid flow arrangement leaking towards chamber 17 andautomatically fed therein.

Various alternative embodiments of the above valves, gates andarrangements are illustrated in FIGURES 1 through 4.

Thus, as shown in FIGURES 1 and 2, in the piston, valves are used forthe control member 22 for the passage from chamber 16 to chamber 17,whereas in FIG- URE 3, the seal element 25 of piston 12 is itself usedto this end, carrying at its center circumferential grooves 25 and beingformed at the lower side with a tapered cross-section, adapted to stopthe flow (position as shown in the figure), whereas, when driven upwardsby a slight downward shift of piston 12, it may release said taperedportion and open the flow from chamber 16 to chamber C9 17. Seal 25abuts at the top on a rim or ring 26 (FIG- URES 1 and 3), and FIGURE 2,respectively.

In FIGURE 3, a guide bearing plug 14 inserted at the lower end of body11, carries valves 23 and 24 interlocked by piece 27, adapted to slideon rod 13 by slight axial shifts. These opposed heads 23 and 24 may thuseither screen flow channels 28 of chamber 17 towards chamber (half viewfrom the left) and expose then passage or channel 29 of chamber 15towards member (halfview from the right), or inversely, member 24screening the latter on behalf of the first.

When closed, member 24 leaves a passage for restrained fiow liquid open,whereas when valve 23 is closed, said member may block any passage fromchamber 17 to chamber 15,

Also shown in the drawings are various arrangements incorporatingself-controlled liquid overflow or circulation channels from chamber 16to chamber 17, at the level 30 of piston 12 in body 11.

At said level, a recess 31 (FIGURE 1) is provided in body 11 which maycorrespond to a clearance 32 outside piston 12, so that said recess andsaid clearance overlap when there is an excess of liquid in chamber 16and when piston 12 lowers, the usual seal 25 in piston 12 is thus facingrecess 31 and ceases to function.

In FIGURE 3, a recess inside body 11 corresponding to the recess 31 isprovided by a plurality of helically shaped channels such as 33, 33'(which may also be longitudinally shaped), the upper ends of which aregenerally at level 30. When piston 12 is lowered in body 11, chambers 16and 17 are in communication through said channels.

In FIGURES 2 and 4, the recess 31 of body 11 is extended up from itsbase on bearing 14 and is covered by an inner sheath or jacket 34 formedwith calibrated openings 35 exposed by piston 12 below level 30 andwhich allow the flow outside cap 18, and with windows 36, adjacentbe-aring 14, and the passage to chamber 17. In FIGURE 3, clearance 29provides for restricted fluid flow between chamber 15 and space 20.

In this type of jacks, the damping according to the invention remainsconventional as a function of the speed of piston 12 in body 11.

When piston 12 is overloaded, the flow of liquid from chamber 15 towardsspace 20 is throttled at the laminar passage or clearance between saidhead or bearing 14 and the inside diameter of the bell-shaped piece 19,or by any other known means provided in said bearing 14.

When piston 12 relieved, the discharge of the liquid from chamber 17towards chamber 16, due to the expansion of the gas in chamber 3, or tothe resilient element, is controlled and restricted by the maximumenergy thereof, the value of which remains an instant function of thepreliminary shift of piston 12. The energies at work are identicallyopposed and, when valve 23 is hermetically closed, they mutually cancelwhatever the residual energetic value possessed at that instant by saidelastic element, so that said damping, complementary to the previousone, may be complete.

In these examples of the jacks as described and illustrated according tothe invention, it is seen that any liquid leakage outside the membersthereof is recovered in a chamber adjacent to the body of these jacksand taken up again below the piston, then re-incorporated into theinitial chamber above the piston, at a constant level, with-outresorting to any auxiliary means, external to said jacks.

What I claim is:

1. A hydraulic jack for a vehicle having a frame and wheels, said jackcomprising a first hollow body having a bottom portion, an open upperend and a first cupshaped member at said open upper end andcornrnunieating with said first body, said first cup-shaped member beingopen at its top; a second cup-shaped member, open at its bottom,attached to the open top of said first cupshaped member; a deformablediaphragm fixed between and extending through said first and secondcup-shaped members and providing therewith two substantially equalchambers respectively below and above said diaphragm; means on saidsecond cup-shaped members for attaching the latter and said first bodyto one part of the vehicle frame and wheels; a second hollow body closedat its bottom and being coaxial with said first body and surrounding andslidably engaging at least a portion thereof; a piston slidably engagingand being mounted coaxially within said first body; a piston rod fastwith said piston; a guide bearing for said piston rod in the bottomportion of said first body; a rigid connection between said piston rodand the bottom end of said second body; means for connecting said pistonrod and with it said second body to that part of the frame and wheelswhich is not connected to said first body; a fluid under pressure in theupper of said two chambers; a fluid in said first body and in the lowerof said two chambers; a passageway in said piston for the passage offluid through said piston from one face thereof to the other within saidfirst body; valve means for closing and opening said passageway; meansin said piston for permitting passage of fluid between said piston andsaid first body from one face of said piston to the other; a first fluidpassage extending through said guide bearing and located between saidpiston rod and the wall of said first body; a second fluid passageextending through said guide bearing and being located between said wallof said first body and the surrounding said second body; valve means foropening and closing said first and second fluid passages; a deformableconvolute diaphragm having two open ends and being concentric with bothsaid first and said second bodies; a fluid tight connection between oneof said ends of said tubular diaphragm and said first body; and a fluidtight connect-ion between the other of said ends of said tubulardiaphragm and said second body.

2. A jack device according to claim 1, wherein a recess is formed insaid first body and a corresponding clearance is formed in said piston,

3. A jack device according to claim 1, wherein circulation channels areprovided between the two portions of said first body on opposite sidesof said piston.

4. A jack device according to claim 1, wherein the portion of said firstbody on one side of said piston extends to said bearing guide.

5. A jack device according to claim 1, wherein said tubular diaphragm isextensible radially outwardly with respect to said first and secondbodies.

References Cited by the Examiner UNITED STATES PATENTS 1,289,082 12/1918Bangs 26764 1,567,515 8/1929 Kijima et al. 188-88 2,064,527 12/1936Ericsson 26764 2,212,259 8/ 1940 Binder 26764 2,436,573 2/ 1948 Heynes.2,719,611 10/1955 Preuihguieres 188100 2,728,419 12/ 1955 Crabtree188-100 3,033,556 5/1962 Wossner 26764 3,074,708 1/1963 Lush et a1.3,128,088 4/ 1964 Paschakarnis.

FOREIGN PATENTS 821,230 10/1959 Great Britain.

870,748 6/1961 Great Britain. 1,087,446 8/1960 Germany.

ARTHUR L. LA POINT, Primary Examiner.

1. A HYDRAULIC JACK FOR A VEHICLE HAVING A FRAME AND WHEELS, SAID JACKCOMPRISING A FIRST HOLLOW BODY HAVING A BOTTOM PORTION, AN OPEN UPPEREND AND A FIRST CUPSHAPED MEMBER AT SAID OPEN UPPER END ANDCOMMUNICATING WITH SAID FIRST BODY, AND FIRST CUP-SHAPED MEMBER BEINGOPEN AT ITS TOP; A SECOND CUP-SHAPED MEMBER, OPEN AT ITS BOTTOM,ATTACHED TO THE OPEN TOP OF SAID FIRST CUPSHAPED MEMBER; A DEFORMABLEDIAPHRAGM FIXED BETWEEN AND EXTENDING THROUGH SAID FIRST AND SECONDCUP-SHAPED MEMBERS AND PROVIDING THEREWITH TWO SUBSTANTIALLY EQUALCHAMBERS RESPECTIVELY BELOW AND ABOVE SAID DIAPHRAGM; MEANS ON SAIDSECOND CUP-SHAPED MEMBERS FOR ATTACHING THE LATTER AND SAID FIRST BODYTO ONE PART OF THE VEHICLE FRAME AND WHEELS; A SECOND HOLLOW BODY CLOSEDAT ITS BOTTOM AND BEING COAXIAL WITH SAID FIRST BODY AND SURROUNDING ANDSLIDABLY ENGAGING AT LEAST A PORTION THEREOF; A PISTON SLIDABLY ENGAGINGAND BEING MOUNTED COAXIALLY WITHIN SAID FIRST BODY; A PISTON ROD FASTWITH SAID PISTON; A GIIDE BEARING FOR SAID PISTON ROD IN THE BOTTOMPORTION OF SAID FIRST BODY; A RIGID CONNECTION BETWEEN SAID PISTON RODAND THE BOTTOM END OF SAID SECOND BODY; MEANS FOR CONNECTING SAID PISTONROD AND WITH IT SAID SECOND BODY TO THAT PART OF THE FRAME AND WHEELSWHICH IS NOT CONNECTED TO SAID FIRST BODY; A FLUID UNDER PRESSURE IN THEUPPER OF SAID TWO CHAMBERS; A FLUID IN SAID FIRST BODY AND IN THE LOWEROF SAID TWO CHAMBERS; A PASSAGEWAY IN SAID PISTON FOR THE PASSAGE OFFLUID THROUGH SAID PISTON FROM ONE FACE THEREOF TO THE OTHER WITHIN SAIDFIRST BODY; VALVE MEANS FOR CLOSING AND OPENING SAID PASSAGEWAY; MEANSIN SAID PISTON FOR PERMITTING PASSAGE OF FLUID BETWEEN SAID PISTON ANDSAID FIRST BODY FROM ONE FACE OF SAID PISTON TO THE OTHER; A FIRST FLUIDPASSAGE EXTENDING THROUGH SAID PLATE BEARING AND LOCATED BETWEEN SAIDPISTON ROD AND THE WALL OF SAID FIRST BODY; A SECOND FLUID PASSAGEEXTENDING THROUGH SAID GUIDE BEARING AND BEING LOCATED BETWEEN SAID WALLOF SAID FIRST BODY, AND THE SURROUNDING SAID SECOND BODY; VALVE MEANSFOR OPENING AND CLOSING SAID FIRST AND SECOND FLUID PASSAGES; ADEFORMABLE CONVOLUTE DIAPHRAGM HAVING TWO OPEN ENDS AND BEING CONCENTRICWITH BOTH SAID FIRST AND SAID SECOND BODIES; A FLUID TIGHT CONNECTIONBETWEEN ON OF SAID ENDS OF SAID TUBULAR DIAPHRAGM AND SAID FIRST BODY;AND A FLUID TIGHT CONNECTION BETWEEN THE OTHER OF SAID ENDS OF SAIDTUBULAR DIAPHRAGM AND SAID SECOND BODY.